The present invention relates to a system for controlling the lamina size in a raw material treatment process for tobacco leaves.
In general tobacco production process, tobacco leaves raw materials are separated each other and then are provided with a flexibility by the addition of water and steam from a humidity controller. Thereafter they are stripped into parenchyma (hereafter referred to as laminae) and veins (hereafter referred to as ribs) and separated into the laminae and ribs by separating machines. The luminae are dried to possess 12% of water content for avoiding change in quality and molding during a long term storage and then packed in a barrel or other container (abovementioned process be referred to as a raw material treatment process). The packed laminae are stored for a long time for maturing. The laminae which have finished maturing are threshed into cut cigarette after the steps of leaf orientation, blending and flavoring.
During the raw material treatment process, the tobacco leaves are stripped into laminae and ribs. The degree of this stripping gives a large influence upon a raw material yield and product quality. That is, the tobacco leaves are subjected to a great mechanical action when they are stripped into laminae and ribs. Accordingly insufficient separation between laminae and ribs is accomplished, or conversely excessive separation is accomplished so that the tobacco leaves are finely divided depending upon the physical properties possessed by the tobacco leaves. The physical properties depend largely on the water content and temperature.
Accordingly, it is important to control the factors which give influence upon the quality, that is, the water content and temperature of the tobacco leaves supplied to rib removing machines so that they are suitable for the tobacco leaves and to control the mechanical impact force upon the tobacco leaves in the rib removing machines to a suitable value for the tobacco leaves.
These controls have heretofore been manually carried out. This manual technique includes adjusting the water content and temperature of the tobacco leaves supplied to the rib removing machines to suitable values by controlling control valves of water and steam of the humidity controller in accordance with a predetermined preset manipulation condition table and adjusting the mechanical impact force given to the tobacco leaves in rib removing machines by replacing a basket with that having a different pitch of grid.
It is however very difficult to manually control the quality of the tobacco leaves while suppressing the production of the laminae not larger than a given size since preliminary determination of the water content and temperature suitable for rib removal and the mechanical impact force applied to the tobacco leaves in the rib removing machine is time and man power consuming due to the fact that the specific physical properties of the tobacco leaves largely varies with the production place, weather conditions of the production year and the like and since it is practically impossible to replace the basket of the rib removing machine depending upon the character of the tobacco leaves which constantly changes.